Chuanmiao Xie1,2,3, Ge Zhang1,2,3, Lin An1,2,3, Xiaoying Chen4,5, Rongxiang Fang6,7. 1. State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China. 2. National Center for Plant Gene Research (Beijing), Beijing, 100101, China. 3. University of Chinese Academy of Sciences, Beijing, 100049, China. 4. State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China. chenxy@im.ac.cn. 5. National Center for Plant Gene Research (Beijing), Beijing, 100101, China. chenxy@im.ac.cn. 6. State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China. fangrx@im.ac.cn. 7. National Center for Plant Gene Research (Beijing), Beijing, 100101, China. fangrx@im.ac.cn.
Abstract
MAIN CONCLUSION: Rice phytochrome-interacting factor-like protein OsPIL15 regulates tiller angle through light and gravity signals in rice. Tiller angle of cereal crops is a key agronomic trait that contributes to grain production. An understanding of how tiller angle is controlled is helpful for achieving ideal plant architecture to improve grain yield. Phytochrome-interacting factors (PIFs) are known to regulate seed germination, seedling skotomorphogenesis, shade avoidance, and flowering in Arabidopsis thaliana. Here, we report that OsPIL15 is, indeed, a rice PIF that negatively regulates tiller angle. Dominant-negative OsPIL15 plants displayed a larger tiller angle, which was associated with reduced shoot gravitropism. Phytochrome B (phyB) is the main photoreceptor perceiving the low red:far-red ratio of shade light. Compared with wild-type rice plants, loss-of-function phyB plants and OsPIL15-overexpressing plants showed smaller tiller angles and enhanced shoot gravitropism. In addition, more OsPIL15 protein accumulated in phyB plants than in wild-type plants. Light regulates the level of the OsPIL15 protein negatively, depending on phyB partially. We propose that OsPIL15 integrates light and gravity signals to regulate tiller angle in rice.
MAIN CONCLUSION: Rice phytochrome-interacting factor-like protein OsPIL15 regulates tiller angle through light and gravity signals in rice. Tiller angle of cereal crops is a key agronomic trait that contributes to grain production. An understanding of how tiller angle is controlled is helpful for achieving ideal plant architecture to improve grain yield. Phytochrome-interacting factors (PIFs) are known to regulate seed germination, seedling skotomorphogenesis, shade avoidance, and flowering in Arabidopsis thaliana. Here, we report that OsPIL15 is, indeed, a rice PIF that negatively regulates tiller angle. Dominant-negative OsPIL15 plants displayed a larger tiller angle, which was associated with reduced shoot gravitropism. Phytochrome B (phyB) is the main photoreceptor perceiving the low red:far-red ratio of shade light. Compared with wild-type rice plants, loss-of-function phyB plants and OsPIL15-overexpressing plants showed smaller tiller angles and enhanced shoot gravitropism. In addition, more OsPIL15 protein accumulated in phyB plants than in wild-type plants. Light regulates the level of the OsPIL15 protein negatively, depending on phyB partially. We propose that OsPIL15 integrates light and gravity signals to regulate tiller angle in rice.
Authors: Judit Soy; Pablo Leivar; Nahuel González-Schain; Guiomar Martín; Céline Diaz; Maria Sentandreu; Bassem Al-Sady; Peter H Quail; Elena Monte Journal: Proc Natl Acad Sci U S A Date: 2016-04-11 Impact factor: 11.205